pushing object into array schema in Mongoose

I have this mongoose schema

var mongoose = require('mongoose');

var ContactSchema = module.exports = new mongoose.Schema({
  name: {
    type: String,
    required: true
  },
  phone: {
    type: Number,
    required: true,
    index: {unique: true}
  },
  messages: [
  {
    title: {type: String, required: true},
    msg: {type: String, required: true}
  }]
}, {
    collection: 'contacts',
    safe: true
});

and trying to update the model by doing this:

Contact.findById(id, function(err, info) {
    if (err) return res.send("contact create error: " + err);

    // add the message to the contacts messages
    Contact.update({_id: info._id}, {$push: {"messages": {title: title, msg: msg}}}, function(err, numAffected, rawResponse) {
      if (err) return res.send("contact addMsg error: " + err);
      console.log('The number of updated documents was %d', numAffected);
      console.log('The raw response from Mongo was ', rawResponse);

    });
  });

I'm I not declaring the messages to take an array of objects?
ERROR: MongoError: Cannot apply $push/$pushAll modifier to non-array

Any ideas?

mongoose does this for you in one operation.

Contact.findByIdAndUpdate(
    info._id,
    {$push: {"messages": {title: title, msg: msg}}},
    {safe: true, upsert: true},
    function(err, model) {
        console.log(err);
    }
);

Please keep in mind that using this method, you will not be able to make use of the schema's "pre" functions.

http://mongoosejs.com/docs/middleware.html

As of the latest mogoose findbyidandupdate needs to have a "new : true" optional param added to it. Otherwise you will get the old doc returned to you. Hence the update for Mongoose Version 4.x.x converts to :

Contact.findByIdAndUpdate(
        info._id,
        {$push: {"messages": {title: title, msg: msg}}},
        {safe: true, upsert: true, new : true},
        function(err, model) {
            console.log(err);
        }
    );

there are two ways for pushing data in array

first way:

let newMessage = {title: "new title", msg: "new Message"}
let result = await Contact.findById(id);
result.messages.push(newMessage);
await result.save();

second way

let result = await Contact.findByIdAndUpdate(
        id,
        {$push: {"messages": {title: title, msg: msg}}},
        {upsert: true, new : true})